We have recruited some patients, but we haven't found any significant result by bronchoscopy in the high risk population.

The purpose of this study is to determine the diagnostic yield of early lung cancer in high risk population, who smokes or has other risk factors, by different bronchoscopy,. Furthermore, another purpose is to determine whether the different bronchoscopy are significant different in diagnosing early lung cancer.

Inclusion Criteria:

• Patient is over 40 years in age and is a heavy cigarette smoker.(smoking index is over 400)
• Patient has been coughing irritably for 2-3 weeks with a failed treatment and without obvious causes.
• The nature of cough changes in a patient who has chronic respiratory disease.
• Patient has blood-stained sputum persistently or repeatedly without obvious causes.

Patient will be included if accorded with any item of above.

Exclusion Criteria:

• Patient has dysrhythmia or cardiovascular disease that poses a risk during exercise.
• Patient has uncontrollable hypertension (SBP > 180mmHg).
• Patient has severe organ dysfunction (shock, severe hepatic and renal dysfunction, massive hemorrhage of upper gastrointestine, diffuse intravascular coagulation(DIC) and massive hemoptysis,etc).
• Patient has blood coagulation disorders (PT>2 times the upper limit of normal(ULN) or Platelet(PLT)<50000/ul）.
• Patient has severe dyspnea.
• Patient is allergic to local anesthetic.
• Patient is unable to provide informed consent.
• Patient is not an appropriate candidate for or is unable to tolerate flexible bronchoscopy procedures.
• Patient has any disease or condition that interferes with completion of initial or follow-up assessments of the effectiveness endpoints.
• Patient has demonstrated unwillingness or inability to complete screening or baseline data collection procedures.
• Patient participated in a study of an investigational drug or device within the past 30 days prior to participation in this study, or is currently participating in another clinical study.
• Patient has pulmonary lesions suspected to be cancer from CT images.
• Female patient of childbearing potential has a positive result from a pregnancy test.

All the patients recruited in the study should meet one item as follows.

• Patient is over 40 years in age and is a heavy cigarette smoker.(smoking index is over 400.)
• Patient has been coughing irritably for 2-3 weeks with a failed treatment and without obvious causes.
• The nature of cough changes in a patient who has chronic respiratory disease.
• Patient has blood-stained sputum persistently or repeatedly without obvious causes.